Polyolefin compositions comprising an heterophasic propylene polymer and polyethylene are well known in the art. For example WO 2006/067023 relates to a polypropylene composition comprising (per cent by weight):                a) 50-77% of a crystalline propylene polymer;        b) 13-28% of an elastomeric copolymer of ethylene and propylene; and        c) 10-22% of polyethylene.        
WO 2006/125720 relates to a propylene polymer composition comprising (per cent by weight):
a) 65-77% of a crystalline propylene polymer,
b) 8 to less than 13% of an elastomeric copolymer of ethylene and propylene; and
c) 10-23% of polyethylene.
These composition are obtained by using Ziegler Natta catalyst with a three steps process, one for each component of the composition.
Even metallocene based catalyst systems have been used for the obtainment of such three components compositions, for example in EP 646 624 examples 21 and 22 this kind of composition is exemplified, however there is always the need of a three steps process or to blend the three components in order to obtain the composition.